Liquid-cooled cylinder heads for internal combustion engines



Jan. 22, 1963 L. R. c. LILLY 3,074,389

LIQUID-COOLED CYLINDER HEADS FOR INTERNAL COMBUSTION ENGINES Filed May 11, 1962 3 Sheets-Sheet 1 INVENTOR LESLIE R. C. LuLLv L. R. c. LILLY 3,074,389

Jan. 22, 1963 LIQUID-COOLED CYLINDER HEADS FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 2 Filed May 11, 1962 iNvEN'roR LESLIE R. C. LILLY hwfw 9wvw ATTORNEYS 1963 L. R. c. LILLY 3,074,389

LIQUID-COOLED CYLINDER HEADS FOR INTERNAL COMBUSTION ENGINES Filed May 11, 1962 3 Sheets-Sheet 3 46 5019 F 6 $4 n; 50A 49 I VENTOR LESLIE R. C. LlLLY A-rTosaNEYs (Iiaires This invention relates to castings constituting liquidcooled cylinder heads for internal combustion engines operating on the four-stroke or two-stroke cycle and of the overhead poppet valve type, that is to say the type having at least one port, controlled by a poppet valve formed in the cylinder head, and is particularly but not exclusively applicable to engines of the liquid fuel injection compression ignition type. For convenience it will be assumed that the cylinder head is applied to the upper end of a vertical cylinder.

Liquid-cooled cylinder heads to which the invention is applicable are of the kind in which the cylinder head consists of a one-piece casting including a cooling liquid space lying between spaced upper and lower walls and a surrounding side wall, with one or more inlet and/or exhaust ports formed in the lower wall while there are provided within the coolin liquid space at least three cast-in hollow bodies each constituting either an inlet or an exhaust passage leading to a port or a housing for a fuel injector or sparking plug or constituting a combustion pocltet, the hollow bodies being di ributed within the plan area of the cylinder head.

An object of the present invention is to provide an arrangement in which adequate cooling of the part of the lower wall which extends between the hollow bodies and the adjacent parts of the hollow bodies can be obtained more readily and efficiently than hitherto.

in a liquid-cooled cylinder head of the kind referred to according to the invention, the castin constituting the cylinder head includes a thickening of the lower wall in the form of an upward projection from the upper surface of the lower wall, between the hollow bodies, such projection having formed in it, as by casting in or drillin coolant passages extending between the hollow bodies in a direction having a substantial component parallel to the plane of the lower wall (and hereinafter for convenience alled horizontal coolant passages), and each horizontal coolant passage communicating at its inner end (that is to say the end which lies adjacent to the area between the hollow bodies) with a coolant passage (herein called for convenience downwardly extending coolant passage) extending downwardly from the upper face of the projection, and circulating means for causing a flow of cooling liquid through the coolant passages in the projection.

In many cases the downwardly extending coolant passage or passages may be comparatively short or be constituted by openings into the inner ends of the horizontal coolant passages.

Conveniently the inner ends of the horizontal coolant passages in the projection communicate with a single common downwar tly extending coolant passage while their outer ends open into the cooling liquid space around the projection.

The circulating means for causing a flow of cooling lic uid through the coolant passages in the projection con veriently comprises a delivery passage or passages arranged to deliver cooling liquid into the upper end or ends of the downwardly extending coolant passage or passages.

The delivery passage or each delivery passage may terminate at a point above the upper end of its associated downwardly extending coolant passage so as to constitute Ea'tentetl San. 22, 1953 a nozzle directing a jet of cooling liquid into such downwardly extending coolant passage.

in one example the cylinder head is of the kind in which the cooling liquid for the cylinder head flows upwards from the water jacket of the associated cylinder into the cooling liquid space of the head through communicating openings formed respectively in the upper face of the cylinder block and the lower face of the cylinder head, and in this case at least one of such openings in the cylinder head may open into the delivery passage so as to deliver the cooling liquid flowing therethrough, either in the form of a jet or otherwise, into the open end of the downwardly extending coolant passage (or one of the downwardly exhausting passages if there be more than one), in the projection. At least a part of the delivery passage may be constituted by a pipe inserted into the cylinder head, or alternatively a part of the delivery passage may be constituted by a passage cast in the cylinder head and arranged to deliver cooling liquid, either directly or through a pipe inserted into the cylinder head, into the upper end of the appropriate downwardly extending coolant passage in the projection.

The invention is particularly applicable to the cylinder heads of internal combustion engines of the compression ignition type in which the cylinder head is provided with inlet and/ or exhaust passages extending from inlet and/ or exhaust ports for the cylinder in the lower wall first upwardly and then laterally to inlet and/ or exhaust openings in the side wall of the cylinder head, and a combustion pocket, for example or spheroidal or similar form, communicating with the cylinder bore through a restricted passage formed in the head or in a plug inserted into the head in known manner. The inlet and/ or exhaust ports and, the combustion pocket, and other hollow bodies in plan view, may be angularly distributed about a vertical axis which may either lie adjacent to or be between the axis of the cylinder bore and at least one of the axes of the hollow bodies. For example, the axes of the inlet and/ or exhaust ports may lie on opposite sides of and be approximately equally spaced from a plane containing the cylinder axis and the axis of the combustion pocket and themselves lie in a plane containing the axis of the cylinder upon which the cylinder head is adapted to be positioned, or displaced from the axis of the cylinder, while the axis of the combustion pocket is substantially displaced from the cylinder axis, e.g. lies on or close to the circumference of the cylinder bore. Thus the axes of the inlet and/ or exhaust ports and of the combustion pocket are angularly distributed, conveniently approximately evenly, about a vertical axis which lies between the axis of the cylinder bore and the axis of the combustion pocket, and the horizontal coolant passages are disposed radially with respect to this vertical axis.

The invention be carried into practice in various ways, but three embodiments will now be described by way of example with reference to the accompanying drawings which show a cylinder head and part of a com pression ignition engine, and in which:

FlGURE l is a horizontal section of a cylinder head according to the present invention for a four-stroke-cycle engine, the section being taken in the plane of three horizontally extending coolant passages formed between the inlet passage, the exhaust passage and the combustion pocket of the cylinder head,

FIGURE 2 is a sectional elevation of part of the cy inder head and part of the associated cylinder block on the line llll of FZGURE 1 in the plane of an inserted feed pipe shown communicating with the cylinder water jacket of the cylinder block,

FIGURE 3 is a sectional side elevation of the cylinder head and part of the cylinder block, on the line llllll of FIGURE 1,

FIGURE 4- is a similar view to that of FIGURE 2 showing a modified construction also as applied to a cylinder head for a four-stroke-cycle engine,

FIGURE 5 is a similar view to FIGURE 1 of a con struction according to the invention as applied to a twostroke-cycle engine, and

FIGURE 6 is a cross section on the line VIVI of FIGURE 5.

The cylinder head of the compression ignition engine shown in FIGURES 1 to 3 comprises a one-piece casting 1 having spaced upper and lower walls 2 and 3, and a surrounding side wall 4 extending between them and defining a water space 6.

The casting I. is also formed with three spaced hollow cast-in bodies, comprising an inlet passage 8, leading from an inlet opening 9 in the side wall 4 of the head to an inlet port it) in the lower wall 3, an exhaust passage 11, leading from an exhaust opening 12 in the side wall 4 to an exhaust port 13, and a combustion pocket 14. These hollow bodies 8, i1 and 14 divide the water space 6 into three parts 6A, 5B and 60 which communicate with one another in conventional manner.

The part of the lower wall 3 between the hollow bodies 8, 11 and 14 is formed with a thickening constituting an upwardly extending projection 35, which is formed with three horizontal passages to which are drilled through apertures 17A, 17B and 17C in the side wall 4 of the cylinder head. The passages communicate at their inner ends with a common downwardly extending passage l8 drilled in the projection through an aperture 19 in the upper wall 2 of the cylinder head.

As shown in FIGURE 2, when the cylinder head is mounted on a cylinder block 2% of a compression ignition engine (illustrated in part), the water space 6 is connected to the cylinder water jacket 21, so as to receive water therefrom, by way of an opening 23 formed in the cylinder block 2% and in alignment with a corresponding opening 24 formed in the cylinder head.

'A water delivery passage in the form of a detachable pipe 25 of generally semi-circular form, and, for example, made of copper, is inserted into the part 6A of the water space through the adjacent aperture 17A in the side wall 4, and one end of the pipe 25 makes a close fit in the opening 24. The other end 26 of the pipe 25 constitutes a nozzle and is positioned over the upper end of the downwardly extending passage 18 into which it directs a jet of water. Thus coolant water is led directly from the cylinder Water jacket 2-1 through the pipe 25 directly into the passages 16 and 18, and hence into the water space 6. The apertures 17A and 1713 in the cylinder head constitute outlet openings for the water, and the apertures 17C and 19, which are screw threaded, are plugged before the cylinder head is positioned on the cylinder block.

Other bores and apertures are formed in the cylinder head in conventional manner. Thus the cylinder head provides a sheath 27 for part of each of two push rods (not shown) adjacent to the water space 6, and between which is an extension of the water space 6. In addition, there are provided vertically extending bores 28 for securing bolts (not shown), and smaller bores 2 constituting steam vents from the block. As shown in FIGURE 3, a spheroidal combustion pocket 14 is provided in a bore 34) with a hot plug 31 containing a restricted passage 32. leading from the combustion pocket 14 into the cylinder bore 22. In the upper wall 2 of the cylinder head are formed bores 33 for poppet valves 34 controlling the inlet and exhaust ports 14 13 and a socket 35 for a fuel-injection device (not shown).

The part of the cylinder head shown in FIGURE 4 is similar to the embodiment shown in FIGURES 1 to 3 and similar parts are given the same reference numerals and will not be escribed again. In this embodiment a detachable pipe 4-9 of cylindrical form and constituting part of a water delivery passage for the downwardly extending passage 18 in which it makes a close fit, is inserted through an aperture 41 in the upper wall 2 of the cylinder head, in which it makes a close fit also. The upper end or" the pipe 49 is closed by a resilient sealing cap 42, and the pipe connects adjacent to its upper end, through a port 43, with the end of a passage 44 cast in the cylinder head constituting the other part of the delivery passage and connecting at its other end with the opening 24. As in the previous embodiment the ports between the hollow bodies, 8, l1 and 14 are cooled by' Water led from the cylinder water jacket 21 through the passage 44 and the pipe 49 directly into the passages 18,

in both these embodiments the three hollow bodies 8, l1 and 14 can be considered approximately evenly angularly distributed about and equidistant from a vertical axis and it will be seen that this axis is coaxial with the downwardly extending passage 18 and is between the axis of the combustion pocket 14 and the axis of the cylinder bore 22 and lies in a plane containing both these axes. This vertical axis between the hollow bodies may lie adjacent to the axis of the cylinder bore or be close to the circumference of the cylinder bore.

The cylinder head shown in EiGURES 5 and 6 is for application to a two-stroke-cycle engine to which air is admitted through inl t ports (not shown) formed in the lower part of the cylinder in conventional manner. The head comprises a casting 45 formed with four exhaust ports as, each controlled by a poppet valve 47 in a manner known per se. Thus in this embodiment there are four hollow bodies cast in an upwardly extending projection 43 of the lower wall of the cylinder head, constituting vertically extending exhaust passages 58A or 563. Each passage sea communicates with an adjacent passage Shh such that both passages lead into one of two parallel horizontally extending exhaust passages 51 and hence to an exhaust opening 52 in a side wall 53 of the cylinder head. Horizontal coolant passages 54 are drilled in the projection between the hollow bodies 58A or 5W5, each coolant passage communicating at its inner end with a common downwardly extending passage 55. Water is delivered from the water jacket of the cylinder block into the upper end of the passage 55 by a generally semi-circular pipe 5:: which extends from an open ing 57 in the lower wall of the cylinder head in alignment with a corresponding opening in the cylinder block, as in FEGURE .2. V

In some cases each horizontal coolant passage in the projection between the hollow bodies may communicate with a separate downwardly extending coolant passage. it will be understood that the invention can be applied to internal combustion engines of the overhead poppet valve type in which there are three or more ports in the lower wall of the cylinder head, e.g. one exhaust port and two inlet ports, distributed over the plan area of the head, with or without a combustion pocket, to cylinder heads in which the hollow bodies are constituted by inlet and exhaust passages and a hollow boss or housing for a fuel injection device or sparking plug housing to engines in which the hollow bodies are constituted by three or more passages each constituting an inlet or an exhaust passage communicating with an inlet or exhaust port in the lower wall, with or without a further hollow body constituted for example by a combustion pocket and/or a fuel injector or sparking plug housing, as well as to engines operating on the two-stroke-cycle in which the hollow bodies are constituted for example by three exhaust passages or two or more exhaust passages and a combustion pocket.

What 1 claim as my invention and desire to secure by Letters Patent is:

1. A liquid-cooled cylinder head structure comprising spaced upper and lower walls and a surrounding side wall defining therebetween a cooling liquid space, at least three cast-in spaced hollow bodies positioned within said cooling-liouid space, said lower wall being formed with a thickened part constituting an upward projection between said hollow bodies, said projection having formed therein horizontal coolant passages extending between said hollow bodies, and a downwardly extending coolant passage extending through the upper face of said projection and communicating with the inner end of each of said horizontal coolant passages, and means arranged to cause cooling liquid to flow through the said coolant passages in the said projection.

2. A cylinder head as claimed in claim 1 in which the outer end of each of said horizontal coolant passages opens into the cooling liquid space around the projection.

3. A cylinder head as claimed in claim 2 including a delivery passage arranged to direct cooling liquid downwardly into the upper end of said downwardly extending coolant passage.

4. A cylinder head as claimed in claim 3 in which at least part of said delivery passage is constituted by a feed pipe inserted into the cylinder head.

5. A cylinder head as claimed in claim 3 in which the said delivery passage terminates above the upper end of said downwardly extending coolant passage to direct a jet of cooling liquid into said upper end.

6. A cylinder head as claimed in claim 3 in which said delivery passage extends from an opening in the lower wall of the cylinder head for receiving cooling liquid from a cylinder block.

7. A cylinder head as claimed in claim 3 in which said delivery passage extends from an opening in the lower wall of the cylinder head and terminates above the upper end of said downwardly extending coolant passage to receive cooling liquid from a cylinder block and to direct a jet of cooling liquid into said upper end.

8. A cylinder head as claimed in claim 1 including a delivery passage constituted by a feed pipe inserted into the cylinder head and arranged to direct cooling liquid downwardly into the upper end of said downwardly extending coolant passage.

9. A cylinder head as claimed in claim 6 in which the said feed pipe terminates above the upper end of said downwardly extending coolant passage to direct a jet of cooling liquid into said upper end.

10. A cylinder head as claimed in claim 1 in which the hollow bodies are angularly distributed about a vertical axis which passes through the said projection and the said horizontal coolant passages are radially disposed in relation to said vertical axis.

11. A liquid-cooled cylinder head structure comprising spaced upper and lower walls and a surrounding side wall defining therebetween a cooling liquid space, and inlet passage, and exhaust passage and a combustion pocket constituting three cast-hi hollow bodies positioned within said cooling liquid space, said lower wall being formed with a thickened part forming an upward projection between said hollow bodies, said projection having formed therein three horizontal coolant passages extending between said hollow bodies, a downwardly extending coolant passage extending through the upper face of said projection and communicating with the inner end of each of said horizontal coolant passages, a delivery passage extending from an opening in the lower wall of the cylinder head and arranged to direct cooling liquid downwardly into the upper end of said downwardly extending coolant passage and to cause cooling liquid to flow through said coolant passages in said projection into said cooling liquid space around said projection.

No references cited. 

1. A LIQUID-COOLED CYLINDER HEAD STRUCTURE COMPRISING SPACED UPPER AND LOWER WALLS AND A SURROUNDING SIDE WALL DEFINING THEREBETWEEN A COOLING LIQUID SPACE, AT LEAST THREE CAST-IN SPACED HOLLOW BODIES POSITIONED WITHIN SAID COOLING LIQUID SPACE, SAID LOWER WALL BEING FORMED WITH A THICKENED PART CONSTITUTING AN UPWARD PROJECTION BETWEEN SAID HOLLOW BODIES, SAID PROJECTION HAVING FORMED THEREIN HORIZONTAL COOLANT PASSAGES EXTENDING BETWEEN SAID HOLLOW BODIES, AND A DOWNWARDLY EXTENDING COOLANT PASSAGE EXTENDING THROUGH THE UPPER FACE OF SAID PROJECTION AND COMMUNICATING WITH THE INNER END OF EACH OF SAID HORIZONTAL COOLANT PASSAGES, AND MEANS ARRANGED TO CAUSE COOLING LIQUID TO FLOW THROUGH THE SAID COOLANT PASSAGES IN THE SAID PROJECTION. 